Digital lighting technologies, i.e. illumination based on semiconductor light sources, such as light-emitting diodes (LEDs), offer a viable alternative to traditional fluorescent, HID, and incandescent lamps. Functional advantages and benefits of LEDs include high energy conversion and optical efficiency, durability, lower operating costs, and many others. Recent advances in LED technology have provided efficient and robust full-spectrum lighting sources that enable a variety of lighting effects in many applications.
With the advent of digital lighting technologies, it is becoming increasingly popular to create lighting networks of LED-based lighting devices. These lighting systems are generally controlled through a network, wherein a data stream containing packets of information is communicated to the lighting devices. Each of the lighting devices may see all of the packets of information, but only respond to packets that are addressed to the particular device. Once a properly addressed packet of information arrives, the lighting device may read and execute the commands. This arrangement demands that each of the lighting devices have an address and these addresses need to be unique with respect to the other lighting devices on the network.
Lighting control for large buildings is generally handled by a building management system (BMS), which controls other aspects besides lighting (e.g. HVAC). Lighting is controlled by a lighting control system (LCS), which is often a component of a BMS. A wire bus is usually used to connect each lighting fixture in a daisy chain fashion back to the LCS. The LCS monitors the status of lighting fixtures within the building and allows remote control of these lighting fixtures, for example, by appropriately placed motion sensors, switches and other switching nodes. It collects statistics on light and power usage and can identify failing light sources, or light sources that are nearing the end of their working life. The LCS can be used to automatically notify maintenance teams when service is required.
Lighting fixtures are typically installed by an electrician in a large building according to a plan that specifies each light or device type, its position and its connection to the wire control bus. However, the identity of each of the installed lighting fixtures is not initially known to the LCS. Thus, the installation must be followed by a commissioning operation, i.e. a set of processes for identifying every lighting fixtures, switch and sensor in a building with the objective of setting up the appropriate control connections between them.
A controller may communicate with a lighting fixture, for example, over a communications network, where the controller controls the light fixture by transmitting commands containing information identifying the target lighting fixture. The controller must know the identifying information of the target fixture in order to send commands to the target fixture. Commissioning, then, may involve associating a physical fixture with a mapped fixture location. For example, each fixture may have a network address associated with it, whereas a building plan assigns a logical identifier to each fixture. The commissioning process associates a network address, such as a numerical identifier code of a fixture, with the logical identifier for that fixture on the building plan.
Commissioning may be performed manually. During the installation, the electrician may install a physical fixture and then manually record the identifier of the fixture on the building plan. The fixtures may then be commissioned by entering the recorded identifier into a fixture database that associates each physical identifier with a fixture in the building plan. Alternatively, a test signal may be used to cycle the power level of each light in turn. An installer or a similar specialist then walks around the building until the light is identified and matched to the plan. This is repeated until all lights are identified. It is then possible to assign each lighting unit to one or more relevant controllers.
Unfortunately, such manual commissioning is typically time consuming. Further, manual provisioning of fixtures may lead to errors, for example, data input mistakes. During the commissioning of a large building with many floors, there may be many commissioning errors. Such commissioning errors may lead to a controller sending commands to the wrong fixture, or commands that appear to have no effect. In such instances, the specialist may be required to debug the system to get it working as intended by the lighting designer. This can involve additional time and expense.
There have been attempts to automate the commissioning process. For example, a method for commissioning installed building service devices uses wireless radio frequency (RF) communication between building service devices to determine spatial positions of each device relative to three or more reference nodes by triangulation of the signal. The coordinates of the determined spatial positions of each device are transmitted to a building services commissioning system, which generates a spatial position map of the devices. This map may then be compared with a building services plan to obtain configuration data for each device. Based on the configuration data, configuration commands may be issued to each device to commission the system.
RF commissioning may be problematic because the ranging accuracy of affordable mass production RF chips is too large; typically greater than 2-5 m (ZigBee/WiFi) based on signal strength measurements. RF chips with greater accuracy, on the order of 50 cm, for example, ultra wide band (UWB) radios that may utilize time-of-flight measurements, are available in very small volumes and are expensive. Further, there is currently poor standardization of UWB radios, making interoperability problematic between different chip suppliers. Further, lighting electronics are normally housed in the ballast of a metal lighting enclosure that shield RF signals, thereby requiring an external antenna, adding further expense, complexity and logistical difficulties to the system.
And so, known techniques for commissioning lighting fixtures according to a building plan are often expensive, error-prone, and/or time-consuming.
Thus, there is a need in the art to reliably commission networked lighting fixtures with minimal expense and complexity. Also, it is desirable to enable commissioning to be done faster and more accurate than conventional commissioning methods. Further, it is desirable for commissioning to be reliably performed by individuals with less specialized skills than, for example, an experienced electrician or a lighting designer.